Status Report on Chromatics Optics Measurements and Correction M. - - PowerPoint PPT Presentation

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Status Report on Chromatics Optics Measurements and Correction M. - - PowerPoint PPT Presentation

Apr 14, 2023 448 likes •545 views

Status Report on Chromatics Optics Measurements and Correction M. Bai, R. Calaga, Y. Luo, S. White 2009 Measurements (R. Calaga et al.) Proposed Correction Initial 2011 Proposal (R. Calaga) => Merged with requests from M. Bai and Y. Luo: 2h

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SLIDE 1

Status Report on Chromatics Optics Measurements and Correction

  • M. Bai, R. Calaga, Y. Luo, S. White
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SLIDE 2

2009 Measurements (R. Calaga et al.)

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SLIDE 3

Proposed Correction

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SLIDE 4

Initial 2011 Proposal (R. Calaga)

=> Merged with requests from M. Bai and Y. Luo: 2h assigned overall, first take measurements

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SLIDE 5

Summary

  • APEX session planned from 6-8am. Summary (from elog):
  • Started ramp at 6:25 only
  • 6:37-7:02: chromaticity, tune adjustments
  • 7:06-7:24: on-momentum measurement for blue and yellow with AC-dipole
  • ~7:30: beams lost during radial steering
  • 7:30-8:00: back to injection, exercised radial, and tune kicker script
  • Achieved on-momentum measurements for both beams simultaneously for the first time
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SLIDE 6

On-momentum Measurements

Blue and yellow beam horizontal measurements: => Measured simultaneously for the first time Blue:

  • IP6: β*~ 0.70 / 0.75
  • IP8: β*~ 0.87 / 0.65

Yellow:

  • IP6: β*~ 0.77 / 0.84
  • IP8: β*~ 0.80 / 0.88
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SLIDE 7

Outstanding Issues

Setting-up the chromaticity: “The other headache is to minimize the tune spread by tweaking chroms at store. Very ineffective in vertical. We tried to change the Blue V chrom in both directions, couldn't get more than 200 turns of coherent

  • scillations. Also, this exercise

indicated that Blue V chrom is on the negative side.” Radial steering: From elog: “Beam was loss due a to a 1.69mm step on the radial steering function which came as a result of starting the function from zero instead of the offset value left in by the orbit feedback.”

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SLIDE 8

Proposal for next Experiment

  • Repeat baseline measurements (AC dipole and tune kicker)
  • Off-momentum optics measurements and correction:
  • Check available range, lifetime at maximum offset
  • Apply corrections (phase advance between IP6 and IP8) + tune feedback
  • Dump, inject ramp, repeat measurements and check for improvements
  • Requirements:
  • 2h beam time
  • 2 ramps / same beam conditions as Wednesday
  • Measurements can be done in common with Yun and Mei, corrections have

to be done separately (different scheme)